Iron Oxide Nanoparticles: Green Synthesis and Their Antimicrobial Activity.

The rise of antimicrobial resistance caused by inappropriate use of these agents in various settings has become a global health threat. Nanotechnology offers the potential for the synthesis of nanoparticles (NPs) with antimicrobial activity, such as iron oxide nanoparticles (IONPs). The use of IONPs is a promising way to overcome antimicrobial resistance or pathogenicity because of their ability to interact with several biological molecules and to inhibit microbial growth. In this review, we outline the pivotal findings over the past decade concerning methods for the green synthesis of IONPs using bacteria, fungi, plants, and organic waste. Subsequently, we delve into the primary challenges encountered in green synthesis utilizing diverse organisms and organic materials. Furthermore, we compile the most common methods employed for the characterization of these IONPs. To conclude, we highlight the applications of these IONPs as promising antibacterial, antifungal, antiparasitic, and antiviral agents.

Antibody induction in mice by liposome-displayed recombinant enterotoxigenic Escherichia coli (ETEC) colonization antigens.

BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) strains cause infectious diarrhea and colonize host intestine epithelia via surface-expressed colonization factors. Colonization factor antigen I (CFA/I), a prevalent ETEC colonization factor, is a vaccine target since antibodies directed to this fimbria can block ETEC adherence and prevent diarrhea. METHODS: Two recombinant antigens derived from CFA/I were investigated with a vaccine adjuvant system that displays soluble antigens on the surface of immunogenic liposomes. The first antigen, CfaEB, is a chimeric fusion protein comprising the minor (CfaE) and major (CfaB) subunits of CFA/I. The second, CfaEad, is the adhesin domain of CfaE. RESULTS: Owing to their His-tag, recombinant CfaEB and CfaEad, spontaneously bound upon admixture with nanoliposomes containing cobalt-porphyrin phospholipid (CoPoP), as well as a synthetic monophosphoryl lipid A (PHAD) adjuvant. Intramuscular immunization of mice with sub-microgram doses CfaEB or CfaEad admixed with CoPoP/PHAD liposomes elicited serum IgG and intestinal IgA antibodies. The smaller CfaEad antigen benefitted more from liposome display. Serum and intestine antibodies from mice immunized with liposome-displayed CfaEB or CfaEad recognized native CFA/I fimbria as evidenced by immunofluorescence and hemagglutination inhibition assays using the CFA/I-expressing H10407 ETEC strain. CONCLUSION: These data show that colonization factor-derived recombinant ETEC antigens exhibit immunogenicity when delivered in immunogenic particle-based formulations.

Comportamiento sexual de pacientes con infección por VIH según grupos de edad / Sexual behavior among patients with HIV according to age groups

Nuestro objetivo fue determinar la prevalencia y conductas de riesgo por grupos de edad entre pacientes con infección por VIH. Se realizó un estudio observacional analítico transversal de pacientes que acuden al servicio de Enfermedades Infecciosas a recibir tratamiento antirretroviral. Resultados: De 117 personas que ingresaron al estudio, se observó que el grupo etario de los jóvenes varones con infección por VIH señalaron una orientación homosexual (HSH) en 64,5% y una mayor tasa de haber sufrido abuso sexual (29%) respecto al resto. En adultos el uso de métodos anticonceptivos es 71,4% y superior al resto de grupos de edad, la concurrencia a lugares de riesgo (visita a trabajadoras sexuales de la calle) se encuentra mayoritariamente en el rango de 45 a 90 años. El rol homosexual activo de los hombres con VIH representa 66,7%. Los hallazgos enfatizan la necesidad de realizar más estudios que profundicen el tema del abuso sexual en adolescentes y adultos jóvenes, debido a la alta prevalencia encontrada en este estudio(AU)

Our objective was to determine the prevalence and risk behaviors by age groups in patients with HIV infection. A cross-sectional analytical observational study of patients attending the Infectious Diseases service to receive antiretroviral treatment was carried out.Results: Out of 117 people who entered the study, it was observed that the age group of young men with HIV infection indicated a homosexual orientation (MSM) 64.5%; and a higher rate of having suffered sexual abuse (29%) in comparison to the others. In adults, the use of contraceptive methods is 71.4%, and higher than the rest of the age groups, attendance at places of risk (visits to street sex workers) is mostly in the range of 45 to 90 years. The active homosexual role of men with HIV represents 66.7%. The findings emphasize the need for more studies that delve into the issue of sexual abuse in adolescents and young adults, due to the high prevalence found in this study(AU)

Population structure of multidrug-resistant Mycobacterium tuberculosis clinical isolates in Colombia.

Emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) isolates is a major public health problem that threatens progress made in tuberculosis (TB) care and control worldwide. In Colombia, the prevalence of MDR tuberculosis (MDR-TB) has increased slowly but steadily since 2001. However, the population structure of the MDR-TB strains circulating in Colombia is sparsely known. In this work, 203 MDR isolates isolated in 2012-2013 were collected, and characterized by spoligotyping, followed by 24-loci MIRU-VNTR (data available for 190 isolates). The most prevalent genotypes corresponded to SIT42/LAM9 (12.81%), SIT62/H1 (10.34%), and SIT190/Beijing (10.34%). A fine analysis showed that although the MDR strains came from 29 of the 33 departments of Colombia, the distribution of these main lineages was not at random and depended on the city of isolation (p-value <0.000001). Both LAM and Beijing lineage strains were significantly associated with MDR-TB (p-value <0.0001): LAM lineage was associated with 2 patterns of MDR, namely combined resistance to INH + Rifampin (HR), and to SHRE (Streptomycin + INH + Rifampin + Ethambutol), while the Beijing lineage strains were essentially associated with MDR (SHRE). Interestingly, distribution of genotypic lineages in function of drug resistance information (e.g. pansusceptible vs. MDR) was different in our setting as compared to other countries in Latin America. However, MIRU-VNTR patterns were unique for all strains, an observation that did not support active transmission of circulating MDR clones.

Comparative genomic analysis of a Shiga toxin-producing Escherichia coli (STEC) O145:H25 associated with a severe pediatric case of hemolytic uremic syndrome in Davidson County, Tennessee, US.

BACKGROUND: Shiga toxin-producing E. coli (STECs) are foodborne pathogens associated with bloody diarrhea and hemolytic uremic syndrome (HUS). Although the STEC O157 serogroup accounts for the highest number of infections, HUS-related complications and deaths, the STEC non-O157, as a group, accounts for a larger proportion of STEC infections and lower HUS cases. There is limited information available on how to recognize non-O157 serotypes associated with severe disease. The objectives of this study were to describe a patient with STEC non-O157 infection complicated with HUS and to conduct a comparative whole genome sequence (WGS) analysis among the patient's STEC clinical isolate and STEC O157 and non-O157 strains. RESULTS: The STEC O145:H25 strain EN1I-0044-2 was isolated from a pediatric patient with diarrhea, HUS and severe neurologic and cardiorespiratory complications, who was enrolled in a previously reported case-control study of acute gastroenteritis conducted in Davidson County, Tennessee in 2013. The strain EN1I-0044-2 genome sequence contained a chromosome and three plasmids. Two of the plasmids were similar to those present in O145:H25 strains whereas the third unique plasmid EN1I-0044-2_03 shared no similarity with other STEC plasmids, and it carried 23 genes of unknown function. Strain EN1I-0044-2, compared with O145:H25 and O157 serogroup strains shared chromosome- and plasmid-encoded virulence factors, including Shiga toxin, LEE type III secretion system, LEE effectors, SFP fimbriae, and additional toxins and colonization factors. CONCLUSIONS: A STEC O145:H25 strain EN1I-0044-2 was isolated from a pediatric patient with severe disease, including HUS, in Davidson County, TN. Phylogenetic and comparison WGS analysis provided evidence that strain EN1I-0044-2 closely resembles O145:H25, and confirmed an independent evolutionary path of STEC O145:H25 and O145:H28 serotypes. The strain EN1I-0044-2 virulence make up was similar to other O145:H25 and O157 serogroups. It carried stx2 and the LEE pathogenicity island, and additional colonization factors and enterotoxin genes. A unique feature of strain EN1I-0044-2 was the presence of plasmid pEN1I-0044-2_03 carrying genes with functions to be determined. Further studies will be necessary to elucidate the role that newly acquired genes by O145:H25 strains play in pathogenesis, and to determine if they may serve as genetic markers of severe disease.

Active and latent tuberculosis among inmates in La Esperanza prison in Guaduas, Colombia.

INTRODUCTION: Active tuberculosis (TB) and latent tuberculosis infection (LTBI) are a public health threat in prisons around the world. The objectives of the study were to estimate the prevalence of LTBI and TB as well as to investigate TB transmission inside one prison, in Colombia. METHODS: A Cross-sectional study was conducted in inmates who agreed to participate. Inmates with respiratory symptoms (RS) of any duration underwent to medical evaluation and three sputum samples were taken for smear microscopy and culture for TB diagnosis. Drug susceptibility was analyzed using BACTEC MGIT 960 and GenoType MTBDRplus. Molecular genotyping of Mycobacterium tuberculosis isolates was performed by 24-Locus MIRU-VNTR and spoligotyping. LTBI was evaluated according to the result of the tuberculin skin test (TST). Close contact investigation was conducted inside the prison for inmates that shared the cell with the index TB case. RESULTS: Among 301/2,020 (15%) inmates with RS of any duration, 8% were diagnosed with active TB. The prevalence of active TB was 1,026 cases/100,000 inmates. We isolated M. tuberculosis in 19/24 (79%) TB cases, 94.7% were susceptible to first line drugs and only one was monoresistant to isoniazid. The most prevalent sub-lineage was Haarlem (68.4%), followed by LAM (26.3%) and T superfamily (5.3%). 24-Locus MIRU-VNTR typing results alone or in combination with spoligotyping identified three clusters containing two isolates each. Two clusters corresponded to inmates that shared the same cell, but each one was located in different blocks of the prison. Inmates from the last cluster were in the same block in nearby cells. TST reading was performed in 95.6% inmates, and 67.6% had a positive reaction. CONCLUSIONS: The prevalence of LTBI and TB was higher in prison than in the general population. Molecular genotyping suggests that TB in this prison is mainly caused by strains imported by inmates or endogenous reactivation.

An integrated practice system for learning programming in Python: design and evaluation.

Over the past decades, computer science educators have developed a multitude of interactive learning resources to support learning in various computer science domains, especially in introductory programming. While such smart content items are known to be beneficial, they are frequently offered through different login-based systems, each with its own student identification for giving credits and collecting log data. As a consequence, using more than one kind of smart learning content is rarely possible, due to overhead for both teachers and students caused by adopting and using several systems in the context of a single course. In this paper, we present a general purpose architecture for integrating multiple kinds of smart content into a single system. As a proof of this approach, we have developed the Python Grids practice system for learning Python, which integrates four kinds of smart content running on different servers across two continents. The system has been used over a whole semester in a large-scale introductory programming course to provide voluntary practice content for over 600 students. In turn, the ability to offer four kinds of content within a single system enabled us to examine the impact of using a variety of smart learning content on students' studying behavior and learning outcomes. The results show that the majority of students who used the system were engaged with all four types of content, instead of only engaging with one or two types. Moreover, accessing multiple types of content correlated with higher course performance, as compared to using only one type of content. In addition, weekly practice with the system during the course also correlated with better overall course performance, rather than using it mainly for preparing for the course final examination. We also explored students' motivational profiles and found that students using the system had higher levels of motivation than those who did not use the system. We discuss the implications of these findings.

Home-cage odors spatial cues elicit theta phase/gamma amplitude coupling between olfactory bulb and dorsal hippocampus.

The brain oscillations may play a critical role in synchronizing neuronal assemblies in order to establish appropriate sensory-motor integration. In fact, studies have demonstrated phase-amplitude coupling of distinct oscillatory rhythms during cognitive processes. Here we investigated whether olfacto-hippocampal coupling occurs when mice are detecting familiar odors located in a spatially restricted area of a new context. The spatial olfactory task (SOT) was designed to expose mice to a new environment in which only one quadrant (target) contains odors provided by its own home-cage bedding. As predicted, mice showed a significant higher exploration preference to the target quadrant; which was impaired by olfactory epithelium lesion (ZnSO4). Furthermore, mice were able to discriminate odors from a different cage and avoided the quadrant with predator odor 2,4,5-trimethylthiazoline (TMT), reinforcing the specificity of the SOT. The local field potential (LFP) analysis of non-lesioned mice revealed higher gamma activity (35-100Hz) in the main olfactory bulb (MOB) and a significant theta phase/gamma amplitude coupling between MOB and dorsal hippocampus, only during exploration of home-cage odors (i.e. in the target quadrant). Our results suggest that exploration of familiar odors in a new context involves dynamic coupling between the olfactory bulb and dorsal hippocampus.

Highly differentiated human airway epithelial cells: a model to study host cell-parasite interactions in pertussis.

BACKGROUND: Bordetella pertussis colonizes the human respiratory mucosa. Most studies on B. pertussis adherence have relied on cultured mammalian cells that lack key features present in differentiated human airway cells or on animal models that are not natural hosts of B. pertussis. The objectives of this work were to evaluate B. pertussis infection in highly differentiated human airway cells in vitro and to show the role of B. pertussis fimbriae in cell adherence. METHODS: Primary human airway epithelial (PHAE) cells from human bronchi and a human bronchial epithelial (HBE) cell line were grown in vitro under air-liquid interface conditions. RESULTS: PHAE and HBE cells infected with B. pertussis wild-type strain revealed bacterial adherence to the apical surface of cells, bacteria-induced cytoskeleton changes, and cell detachment. Mutations in the major fimbrial subunits Fim2/3 or in the minor fimbrial adhesin subunit FimD affected B. pertussis adherence to predominantly HBE cells. This cell model recapitulates the morphologic features of the human airway infected by B. pertussis and confirms the role of fimbriae in B. pertussis adherence. Furthermore, HBE cells show that fimbrial subunits, and specifically FimD adhesin, are critical in B. pertussis adherence to airway cells. CONCLUSIONS: The relevance of this model to study host-parasite interaction in pertussis lies in the striking physiologic and morphologic similarity between the PHAE and HBE cells and the human airway ciliated and goblet cells in vivo. These cells can proliferate in vitro, differentiate, and express the same genetic profile as human respiratory cells in vivo.

Phenotypic and genotypic characterization of enterotoxigenic Escherichia coli clinical isolates from northern Colombia, South America.

Enterotoxigenic Escherichia coli (ETEC) are major causes of childhood diarrhea in low and middle income countries including Colombia, South America. To understand the diversity of ETEC strains in the region, clinical isolates obtained from northern Colombia children were evaluated for multiple locus sequencing typing, serotyping, classical and nonclassical virulence genes, and antibiotic susceptibility. Among 40 ETEC clinical isolates evaluated, 21 (52.5%) were positive for LT gene, 13 (32.5%) for ST gene, and 6 (15%) for both ST and LT. The most prevalent colonization surface antigens (CS) were CS21 and CFA/I identified in 21 (50%) and 13 (32.5%) isolates, respectively. The eatA, irp2, and fyuA were the most common nonclassical virulence genes present in more than 60% of the isolates. Ampicillin resistance (80% of the strains) was the most frequent phenotype among ETEC strains followed by trimethoprim-sulfamethoxazole resistance (52.5%). Based on multiple locus sequencing typing (MLST), we recognize that 6 clonal groups of ETEC clinical isolates circulate in Colombia. ETEC clinical isolates from children in northern Colombia are highly diverse, yet some isolates circulating in the community belong to well-defined clonal groups that share a unique set of virulence factors, serotypes, and MLST sequence types.

Discriminação de incrementos de desflorestamento na Amazônia com dados SAR R99B em banda L / Discriminating deforestation increment areas in the Amazon rainforest with L band SAR R99B data

O uso de dados de sensoriamento remoto óptico em projetos de monitoramento de extensas áreas de floresta tropical é limitado devido à intensa cobertura por nuvens. Os dados SAR (Synthetic Aperture Radar) podem ser uma alternativa interessante para detectar desflorestamento nas regiões de floresta tropical onde a cobertura por nuvens é permanente. Neste contexto, o objetivo deste trabalho é avaliar o potencial do dado SAR adquirido em banda L pelo sistema aerotransportado R99B da Força Aérea Brasileira (FAB) para discriminar incremento de desflorestamento na Amazônia. Para tanto, foram realizadas classificações MAXVER-ICM com dados SAR multipolarizados de uma área teste localizada na região Sudeste do Estado do Acre. As classificações realizadas com a combinação dos canais HH, HV e VV e com o par de polarizações HH+HV obtiveram boa concordância com o mapa produzido no projeto PRODES (k = 0,68, onde k é o índice Kappa), o qual foi adotado como dado de referência. Este resultado indica que o dado SAR multipolarizado em banda L possui bom potencial para discriminar incremento de desflorestamento na Amazônia.

The use of optical remote sensing data in large tropical forest regions has an important limitation due to cloud cover. Synthetic Aperture Radar (SAR) data can be a viable alternative in areas where cloud cover is permanent, because the data acquisition is independent on atmospheric conditions. In this context, the main objective of this work was to evaluate the potential of L band SAR data acquired by R99B Brazilian Air Force (FAB) airborne system to discriminate deforestation increments in the Amazon rainforest. In order to achieve this purpose, we performed Maximum Likelihood classifications with multipolarized SAR data of a test site located in the state of Acre. The classifications performed with the combination of three channels (HH+HV+VV) and with the polarization pair HH+HV obtained good agreement with PRODES reference map (k=0,68, where k is de Kappa index). This result indicates that multipolarized L band SAR data have good potential to discriminate deforestation increments in the Amazon rainforest.

Detection of Escherichia coli enteropathogens by multiplex polymerase chain reaction from children's diarrheal stools in two Caribbean-Colombian cities.

Acute diarrheal disease is a leading cause of childhood morbidity and mortality in the developing world and Escherichia coli intestinal pathogens are important causative agents. Information on the epidemiology of E. coli intestinal pathogens and their association with diarrheal disease is limited because no diagnostic testing is available in countries with limited resources. To evaluate the prevalence of E. coli intestinal pathogens in a Caribbean-Colombian region, E. coli clinical isolates from children with diarrhea were analyzed by a recently reported two-reaction multiplex polymerase chain reaction (Gomez-Duarte et al., Diagn Microbiol Infect Dis 2009;63:1-9). The phylogenetic group from all E. coli isolates was also typed by a single-reaction multiplex polymerase chain reaction. We found that among 139 E. coli strains analyzed, 20 (14.4%) corresponded to E. coli diarrheagenic pathotypes. Enterotoxigenic, shiga-toxin-producing, enteroaggregative, diffuse adherent, and enteropathogenic E. coli pathotypes were detected, and most of them belonged to the phylogenetic groups A and B1, known to be associated with intestinal pathogens. This is the first report on the molecular characterization of E. coli diarrheogenic isolates in Colombia and the first report on the potential role of E. coli in childhood diarrhea in this geographic area.

Tratamento do câncer de pequenas células de pulmão: doenca limitada: resultados de uma única instituicão / Treatment of limited stage small-cell lung cancer: results from a single center

OBJETIVO: Relatar os resultados de tratamento de pacientes com câncer de pulmão de pequenas células com doenca limitada (CPPC-DL), num período de dez anos, numa única instituicão, para controle de qualidade e comparacão com dados de literatura. MATERIAIS E MÉTODOS: Entre janeiro de 1992 e dezembro de 2002, 101 pacientes portadores de CPPC-DL completaram tratamento em nossa instituicão. Seus resultados foram revistos e incluíram quimioterapia, radioterapia, a seqüência dos dois tratamentos e o uso de irradiacão profilática cerebral (PCI). A radiacão foi administrada com dose mediana de 45 Gy em 1,8 a 2 Gy por fracão. A dose mediana de PCI foi de 25 Gy em dez fracões. RESULTADOS: O seguimento mediano foi de 50,6 meses e a idade mediana dos pacientes foi de 63 anos. Houve 85 mortes confirmadas, 5 pacientes foram perdidos de seguimento e 11 estavam vivos. O tempo de sobrevida mediano foi de 11 meses, a sobrevida global em dois e cinco anos foi de 25,5 por cento e 10 por cento, respectivamente. Não houve diferenca significante na sobrevida global em dois ou cinco anos segundo a idade e sexo dos pacientes. Também não houve diferenca significante na sobrevida global entre os pacientes que realizaram PCI ou não, ou foram tratados em dois períodos diferentes (1997-2002 vs. 1992-1996). CONCLUSAO: Os resultados de tratamento dos pacientes portadores de CPPC-DL na nossa instituicão refletem as constantes mudancas no manuseio do CPPC. Nossa sobrevida global em dois anos de 25,5 por cento é semelhante a outros resultados uni-institucionais publicados, mas menor que os resultados de 47 por cento a 54 por cento recentemente publicados por grupos cooperativos.

[Weight maintenance in humans. Could it mimic calorie restriction of animal models?]. / La mantención de peso en humanos podría ser equivalente a la restricción calórica de los modelos animales?

BACKGROUND: Energy restriction (ER) extends life span in animals, by decreasing oxidative stress. AIM: To compare adiposity, metabolic variables and DNA oxidative damage, among adults, reporting a constant body weight (weight maintainers), versus those reporting a progressive increase (weight gainers). SUBJECTS AND METHODS: Clinical history, dietary recall, anthropometric measures, abdominal CT scan and fasting blood samples (to measure lipoproteins, glucose and insulin), were obtained in 44 males. These subjects were classified as weight maintainers if they had a change in weight of 3 kg or less in the last 10 years, or weight gainers, if they had a weight increment of more than 6 kg, in the same lapse. Oxidative damage was assessed by 8-hydroxydeoxyguanosine (8-OHdG), in DNA extracted from circulating lymphocytes, in 5 weight maintainers, 8 weight gainers and 5 healthy elders. RESULTS: Energy Intake was 18% higher in weight gainers (p <0.01). Adiposity and central fat were higher among weight gainers (p <0.01). Abdominal fat correlated with serum lipoproteins, glucose and insulin sensitivity, assessed by the Homeostasis Model Assessment (HOMA). 8-OHdG levels did not differ between groups. CONCLUSIONS: The analysis of weight change based on the clinical history correlates with actual body composition, thus it may be a reliable indicator of long term energy Intake. This method could be comparable to weight clamp models employed in animals to study aging.